The present invention relates to a vacuum picking system for picking up and moving sheet media, such as banknotes, and in particular a valveless vacuum picking system. The present invention also relates to a self-service terminal such as an automated teller machine that includes such a system.
Vacuum picking systems are used in automated teller machines for dispensing cash. Most of these include some form of pump mechanism for sucking air through a tube, which tube has a suction pad on its end. When the suction pad is moved into contact with a banknote the suction created by the pump causes the banknote to stick to the pad. This effectively closes the end of the pad, and the tube. Continued action of the pump causes the pressure in the tube to lower, so that the banknote can be securely held in place. Once so secured, the banknote can be moved as and when desired.
Most automated teller machines include a plurality of vacuum picking modules so that different denominations of banknotes can be dispensed. For example, in the UK, typically four modules are provided, two of which may include twenty-pound notes and the other two of which may include ten-pound notes. In order that notes can be dispensed, each module has to have a separate banknote pick-up mechanism, each with its own pickline. FIG. 1 shows one known vacuum-based system, in which each pickline is connected to an individual pump, and each of the pumps is connected to a single AC motor. Associated with each pickline is a solenoid valve for opening or closing the line so that air can be selectively evacuated thereform. Also associated with each line is gearing or other mechanical means (not shown) for moving the end of the pickline into contact with the banknote, and then towards a dispensing location. This gearing is powered by the AC motor.
In use, when cash is to be dispensed from the system of FIG. 1, the motor is switched on and all of the pumps are run simultaneously. Because the motor also powers the gearing, this means that all of the gearing is caused to move. Once the pump is running, one of the valves is opened so that air is drawn through the associated pickline. The end of the pickline, which usually carries a suction cap, is then is moved towards the banknote until it is in contact therewith. As described previously, this causes the banknote to stick to the cap so that it can be removed under the action of the vacuum.
FIG. 2 shows another known arrangement. In this, a single pump driven by a single motor is used to create a pressure difference in a selected one of the pick-up lines and drive a gearing mechanism for moving the pickline between pick-up and release positions. Each of the picklines is provided as a separate branch of a single line that is connected directly to the pump. Provided in each pickline is a solenoid valve. By selectively opening and closing the solenoid valves as appropriate, a selected one of the picklines can be exposed to the pump and so used for a pick and place action. In use, the motor is switched on to power the pump. Because the motor also powers the gearing, this means that all of the gearing is caused to move. Once the pump is running, one of the valves is opened so that air is drawn through the associated pickline and the suction cap on the line is moved towards the banknote until it is moved into contact therewith, and removed as described previously.
Various problems arise with the arrangements of FIGS. 1 and 2. For example, a relatively large AC motor is needed, which reduces the level of control that can be exercised. Also, because all the pumps are run simultaneously, the power requirements, and so operational costs, are relatively high. In addition, because all of the gearing is run when the motor is on, this means that wear can be significant. Furthermore, both of the systems of FIGS. 1 and 2 require a solenoid valve in each pickline. Since solenoid valves can be difficult to control, this increases the complexity of the system.